The pelvic restraint of the present invention is an improvement over previous pelvic restraint devices utilized in exercise apparatus, particularly low back exercise apparatus, since it more securely restrains the pelvis therein and minimizes movement of the pelvis relative to the restraint device. This results in improved repeatability and accuracy of data relating to back movement generated by a low back exercise apparatus. Previous pelvic restraints have allowed for lifting of one or both hips, lateral movement of the hips, and forward and rearward pitching of the pelvis due to the lack of proper restraint. Moreover, the pelvic restraint of the present invention accommodates a larger range of buttocks than has been possible with previous pelvic restraints. Prior pelvic restraints known to the applicant are generally comprised of a padded seat and back and have a belt secured at each end thereof to a support fixedly attached to the seat back. As noted above, this type of pelvic restraint structure allows for unacceptable hip movement relative to the restraint in view of its inherent inadequate stabilization of the pelvis in relation to the restraint.